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Biomedical subjects

N Ishihara

Publications and source records attributed to N Ishihara.

At least 109 records · Page 6Linked to original sources
PubMed1986

[Characteristics of early carcinoma of the gallbladder--clinico-pathological study].

53 early carcinomas of the gallbladder in 46 cases were studied. They were surgically resected and limited to the proper muscle layer and/or Rokitansky-Aschoff sinus. 19 percent of them were pointed out by preoperative examination, and 34 percent during the operation. Finally, 85 percent of them were macroscopically with formalin-fixed materials. 53 carcinomas were composed of 14 protruded type carcinomas (26%) and 39 superficial type ones (74%). 21 tumors (40%) were pure flat (II b) type carcinomas and 17 (32%) were tumors having flat (II b) area. In the latter, flat (II b) area spread widely in the carcinoma lesion. The early carcinomas had areas of 0.01 to 80 cm2 (average 16.1 cm2). 29 percent of them occupied wider area than the half of the resected gallbladder.

Adult↗
PubMed1985

Tyrosine phosphorylation of platelet protein induced by phorbol ester.

The presence of phosphotyrosine in proteins from washed rabbit platelets was demonstrated by electrophoresis and by alkali stability of phosphorylated polypeptides. The phosphotyrosine content increased about twofold by treating the platelets with PMA in spite of the fact that the specific activity of labeled ATP was unchanged. It was shown that phosphorylated proteins with apparent molecular weight of 48k, 53k and 250k were alkali-stable. Although phosphorylation of 48k protein in platelets was stimulated by 1 U thrombin as well as by 100 ng PMA, only the phosphorylated samples from PMA-treated platelets were alkali-stable. The 48k protein from platelets stimulated by PMA showed the fivefold increase of 32P-tyrosine content as compared with the control. Relatively lower increase of 32P-serine or 32P-threonine, 2- and 1.7-fold respectively, was thereby observed. The differences in time-sequence between 48k and 250k protein of total and alkali-stable phosphorylations suggested that tyrosine phosphorylation of 48k protein is the earliest event after the PMA-stimulation.

Animals↗
PubMed1984

Increased o- and p-cresol/hippuric acid ratios in the urine of four strains of rat exposed to toluene at thousands-ppm levels.

Rats (Fisher, Wistar, Donryu and Sprague-Dawley strains) were exposed to 5 approximately 3500 ppm toluene for 8 h, and urine samples were analyzed for hippuric acid and cresols. While hippuric acid increased in proportion to the exposure concentration, a sharp increase in o-cresol excretion was observed at high toluene concentrations so that the o-cresol/hippuric acid ratio was elevated after 500 approximately 3500 ppm exposures. Changes in the p-cresol: hippuric acid ratio were less marked. There were strain differences in toluene metabolism. Fisher rats were highest and Sprague-Dawley rats lowest in o-cresol excretion and in the o-cresol: hippuric acid ratio, whereas Wistar rats excreted p-cresol most abundantly.

Animals↗
PubMed1984

Lead and zinc concentrations in plasma, erythrocytes, and urine in relation to ALA-D activity after intravenous infusion of Ca-EDTA.

Lead and zinc concentrations in plasma, erythrocytes, and urine, urinary ALA concentration, and ALA-D activity in blood were studied for four hours in two male lead workers during and after a one hour infusion of Ca-EDTA 2Na. Urinary and plasma lead concentrations increased as a result of administering Ca-EDTA 2Na, and the ratios of lead concentrations in plasma to those in urine were greatly increased. The increase of plasma lead concentration was not due to the haemolytic effect of Ca-EDTA 2Na but was mobilised lead, rapidly excreted in the urine. ALA-D activity in blood increased at the end of the experiment with a transient decrease during the infusion of Ca-EDTA 2Na. As zinc concentrations in erythrocytes and plasma did not decrease during the infusion despite an increase in the urinary excretion of zinc, the transient decrease of ALA-D activity was not due to a loss of zinc caused by Ca-EDTA 2Na. From the results of additional experiments in vitro, this transient decrease could be related neither to Ca-EDTA 2Na nor to lead in the blood.

Creatinine↗
PubMed1979

Regional cerebral blood flow, diaschisis, and steal after stroke.

Regional CBF was measured by 133Xe inhalation in unilateral cerebral infarction, carotid TIAs, and normal volunteers. Regional CBF values were bilaterally and symmetrically reduced in patients measured within 3 weeks after stroke. Later, rCBF values returned toward normal in the contralateral hemisphere of patients with infarction and in both hemispheres with carotid TIAs. In cases with carotid occlusive disease, flow reduction was seen in the contralateral posterior cerebral artery distribution, with hyperemia in ipsilateral occipital lobe caused by interhemispheric steal. Brainstem-cerebellar flow values were increased following acute cerebral infarction if patients were alert but reduced if consciousness was impaired.

Adult↗
PubMed1979

Influence of cerebral embolism on brain monoamines.

In baboons the right cerebral hemisphere was embolised by a shower of microemboli, immediately followed by one large embolus designed to occlude the middle cerebral artery (MCA). One hour after embolism a significant, though small, reduction in blood flow and oxygen consumption of the embolised hemisphere was recorded, at which time the animals were killed and brain monoamines measured. Dopamine was reduced in the ipsilateral caudate nucleus, the reported site of maximal ischaemic damage in this model. Dopamine levels were increased in frontal and occipital grey matter sampled from areas surrounding the occluded MCA territory and in similar brain areas of the opposite non-embolised hemisphere. Noradrenaline was increased in grey matter from both cerebral hemispheres, as well as subcortical structures bilaterally. Brain 5-hydroxytryptamine levels were unaltered, but increased 5-hydroxyindoleacetic acid in cisternal cerebrospinal fluid suggested transient alteration in 5-hydroxytryptamine metabolism after embolism. The effects of cerebral embolism on brain monoamine metabolism appear to be different from the effects of permanent surgical occlusion of major cerebral vessels. The bilaterality of effects after unilateral hemispheric embolism might be related to diaschisis. The mechanisms of the observed changes, as well as their relevance to the progression of cerebral ischaemia and the complications associated with cerebral embolism, still require to be established.

Animals↗
PubMed1978

Differences in the time course of regional cerebral hemo-dynamics of gray and white matter during experimental hypertension.

Investigations concerned with the pathogenesis of hypertensive encephalopathy have reported two opposing changes in cerebral hemodynamics during induced hypertension: (1) vasospasm or vasoconstriction of the leptomeningeal arteries and (2) increase of cerebral blood flow which has been termed "breakthrough" of the cerebral autoregulation. To resolve this apparent conflict, continuous measurements of focal cerebral flow and oxygen availability were made in 17 baboons by the use of implanted platinum electrodes placed in both gray and white matter during induced hypertension. Autoregulation was initially well maintained in gray matter followed by "breakthrough" but the autoregulatory response was poorly maintained in the cerebral white matter. The vasoconstriction of the leptomeningeal arteries reported in earlier investigations from observations made through a skull window appears to be due to a marked autoregulatory response to hypertension rather than vasospasm. The autoregulatory response appears to be efficient in gray matter but relatively deficient in white matter.

Acute Disease↗
PubMed1978

Cerebral tissue response to electrode implantation.

Tissue response to platinum electrodes was assessed after an eight-day implantation period. The regions of study included the cortical areas at the opercular gyri and at the sulcus parieto-occipitalis externus, as well as the sub-cortical white matter in these cases. Perivascular and intraparenchymal hemorrhagic lesions as well as edematous changes characterized both by extensive intra and extracellular swelling were noted. Numerous phagocytic elements and degenerative strucutres were present at the electrode/parenchymal interface. Tissue alterations were asymmetrical as observed both around and at the tip of the implanted electrode. The parenchymal alterations extended from 0.2mm to 3.5mm distance from the electrode path/parenchymal interface. Greater tissue involvement was found in the subcortical white matter as compared to the adjacent cortical gray matter.

Animals↗
PubMed1978

An automated system for the determination of lead in blood, manganese in urine and nickel in waste water.

An automated system has been developed to analyze lead in blood, manganese in urine and nickel in waste water at a rate of 20 to 30 samples per hour. The analysis is based on direct chelation without digestion, extraction into methyl isobutyl ketone and flame atomic absorption spectrophotometry. The applicability of the system in the field of occupational and environmental medicine is discussed.

Autoanalysis↗
PubMed1978

Detection of Epstein-Barr virus in biopsied malignant lymphoma cell and its continuous culture.

In more than 80% of tumor cells in the pericardiac effusion of a case of malignant B-cell lymphoma, Epstein-Barr virus-determined nuclear antigen (EBNA) was detected by the anticomplement immunofluorescence test. Moreover, herpestype virus particles, although few in number, were demonstrated in the nucleus of lymphoma cells by an electron microscope. Tumor cells in the pericardiac effusion were seeded at 98% purity after centrifugation on Ficoll-Conray and, soon after plating, they proliferated continuously without any lag phase of growth or cell death. Therefore, the established cell line was regarded as of tumor cell origin and named Fujimaki-II cell after patient's name. On the other hand, Fujimaki-I cells were established from the biopsied tumor in the same way. These two cell lines, B-lymphocyte in nature, had both EB virus-related antigens and herpes-types virus particles. Heterotransplantation of cultured cells and tumor tissue obtained at autopsy into athymic nude mice was not successful. Transformation of cord blood lymphocytes by the virus released from Fujimaki-II cell also failed. This might be the first case of non-Burkitt type lymphoma in which the EB virus genome was directly detected in the tumor cells.

Antigens, Viral↗